1. Field of the Invention
The present invention relates to a pad clip, used in a disc brake of a vehicle, for preventing a pad from being rattled in non braking time and pulling the pad apart from a side face of a rotor in accordance with releasing braking.
2. Related Art
A disc brake is widely used for braking a vehicle. In braking by the disc brake, a pair of pads arranged on both sides in an axial direction of a rotor rotated along with a wheel is pressed to both side faces of the rotor by pistons. Although there are known such disc brakes having various structures in a background art, an opposed piston type disc brake provided with pistons on both sides of the rotor in a state of being opposed to each other achieves a stable brake force. Therefore, in recent years, examples of use of the opposed piston type disc brake are increased. JP-A-09-089018 and JP-A-2005-121174 respectively describe examples of such an opposed piston type disc brake.
FIGS. 8 through 10(C) show a structure described in JP-A-09-089018. A disc brake 1 is provided with a caliper 5 provided with an outer body portion 3 and an inner body portion 4 at a position interposing a rotor 2, and an outer cylinder 6 and an inner cylinder 7 are provided in the respective body portions 3, 4 in a state of making opening portions of the respectives opposed to each other by way of the rotor 2. Further, an outer piston 8 and an inner piston 9 are mounted into the outer cylinder 6 and the inner cylinder 7 in liquid tight and displaceably in an axial direction of the rotor 2 (up and down direction of FIGS. 1, 5, 8 and 11, obverse and reverse direction of FIGS. 2, 6 and 12, left and right direction of FIGS. 3, 7, 10(A), 10(B), 10(C) and 13). Further, an outer pad 10 and an inner pad 11 are arranged so as to be displaceable in the axial direction of the rotor 2 at portions proximate to outer sides in a radial direction of an outer peripheral edge of the rotor 2 in a state of being respectively hung from pins 12, 12 made to bridge the outer body portion 3 and the inner body portion 4. Through holes are respectively formed at outer peripheral edge portions of pressure plates 13, 13 of the two pads 10, 11, and the respective pins 12, 12 are loosely inserted into the respective through holes.
A pad clip 14 is arranged between the respective pins 12, 12 and the outer pad 10 and the inner pad 11. As shown by FIG. 10 (A), the pad clip 14 is constituted by coupling two sheets of metal plates 15a, 15b respectively having an elasticity in a state of being intersected with each other. The metal plate 15a is arranged in parallel with a rotational direction of the rotor 2 (left and right direction of FIGS. 1, 2, 5, 6, 8, 11 and 12) between the two pads 10, 11. In contrast thereto, the metal plate 15b is arranged in parallel with the axial direction of the rotor 2 substantially at a center portion in the rotational direction of the rotor 2 of the two pads 10, 11.
Further, both end portions of the metal plate 15a in the rotational direction of the rotor 2 are constituted by fold-to-bend portions 16, 16 folded to bend to an inner side in the radial direction respectively in a crank-like shape, and the two fold-to-bend portions 16, 16 are engaged with peripheral faces on the inner side in the radial direction of the respective pins 12, 12. Further, both end portions in the axial direction of the rotor 2 of the metal plate 15b on other side are respectively folded back to inner sides to constitute elastic engaging portions 17, 17. Further, inner side faces in the radial direction of the two elastic engaging portions 17, 17 are brought into elastic contact with outer peripheral edge portions and substantially at center portions in the rotational direction of the rotor 2 of the pressure plates 13, 13 of the two pads 10, 11.
According to the disc brake 1 constituted as described above, during braking, a pressurized oil is fed into the outer cylinder 6 and the inner cylinder 7 to press linings 24, 24 of the outer pad 10 and the inner pad 11 to two inner and outer side faces of the rotor 2 by the outer piston 8 and the inner piston 9. Further, in accordance with releasing braking, the two pads 10, 11 are pulled apart from the side faces of the rotor 2 by elastic forces exerted from the two elastic engaging portions 17, 17 constituting the pad clip 14. On the other hand, during non braking time, by the two elastic engaging portions 17, 17, elastic forces directed to the inner side in the radial direction are exerted to the two pads 10, 11 to prevent the two pads 10, 11 from being rattled relative to the caliper 5.
Further, JP-A-09-089018 mentioned above also respectively describes a pad clip 14a formed by a single sheet of a metal plate as shown by FIG. 10 (B), and a pad clip 14b forming elastic engaging portions 17a, 17a constituting portions of elastically pressing the two pads 10, 11 by folding to bend the elastic engaging portions 17a, 17a in directions in which the more proceeding to front end portions thereof, the more directed to outer sides in the radial direction without folding back the elastic engaging portions 17a, 17a. 
In a case of the structure described in JP-A-09-089018 mentioned above, by the pad clips 14, 14a, 14b, only the center portions in the rotational direction of the outer pad 10, the inner pad 11 are pressed. Therefore, there is a possibility that attitudes of the two pads 10, 11 are difficult to be stabilized, the two pads 10, 11 are locally brought into contact with the rotor 2, and uneven wear is brought about at the linings 24, 24 constituting the two pads 10, 11. Further, in the pad clips 14, 14a, 14b, the pad clip 14 shown in FIG. 10(A) needs to couple two sheets of the metal plates 15a, 15b, and therefore, fabrication cost is increased.
On the other hand, in cases of the pad clips 14a, 14b shown in FIGS. 10(B) and 10(C), although the pad clips 14a, 14b are formed by one sheet of a metal plate, it is necessary to constitute a material plate before being folded to bend to form by a cross shape. Such a material plate is provided by successively punching a metal plate constituting a material by a predetermined shape. Therefore, it is requested to make the interval between the contiguous material plates as narrow as possible. However, in a case of the material plate in the cross shape as described above, the interval between the contiguous material plates becomes wide. As a result, an unused portion of the metal plate constituting the material is increased (blanking performance is not good=yield of material is poor). Further, in the case of the pad clip 14a shown in FIG. 10(B), the elastic engaging portions 17, 17 are formed by being folded back. Therefore, a dimension of the material plate before being folded back is increased, and the blanking performance (yield) is further deteriorated.
On the other hand, JP-A-2005-121174 describes a structure capable of stabilizing attitudes of an outer pad and an inner pad. FIGS. 11 through 13 show a disc brake 1a described in JP-A-2005-121174. The disc brake 1a is provided with a caliper 5a arranged in a state of riding over the rotor 2 rotated along with a wheel. The caliper 5a is integrally produced by a material made of an aluminum alloy and includes an outer body portion 3a and an inner body portion 4a arranged on both sides in the axial direction of the rotor 2, and a pair of connecting portions 18, 18 connecting both end portions in a rotational direction of the two body portions 3a, 4a. 
A pair of outer side coupling pins 19, 19 are provided at portions of middle portions in a rotational direction of the outer body portion 3a and the inner body portion 4a disposed between the two connecting portions 18, 18, between outer end portions in a radial direction respectively in a state of being made to bridge the two body portions 3a, 4a. Further, one piece of a middle coupling pin 20 is provided in a state of being made to bridge the two body portions 3a, 4a. The respective coupling pins 19, 20 are constituted by a circular tube shape by a ferrous alloy constituting a metal material having a Young's ratio larger than that of the aluminum alloy respectively constituting the caliper 5a. 
The two outer side coupling pins 19, 19 in the respective coupling pins 19, 20 respectively having such shapes are provided at portions proximate to outer sides in the radial direction of an outer peripheral edge of the rotor 2 at positions interposing pressure plates 13a, 13a of an outer pad 10a and an inner pad 11a. Further, the middle coupling pin 20 is provided at portions on outer sides in the radial direction of the two pads 10a, 11a and between the outer side coupling pins 19, 19. Further, a pad clip 14c is provided between the middle coupling pin 20 of the respective pins 19, 20 and outer peripheral edges in the radial direction of the pressure plates 13a of the two pads 10a, 11a. 
The pad clip 14c is made of an elastic material of a stainless spring steel plate or the like and is provided with a center engaging portion 21 and press arm portions 22, 22 respectively constituted by a T-like shape provided on both sides in a rotational direction of the center engaging portion 21. The center engaging portion 21 there among is provided with a section in a shape of a circular arc an outer side in the radial direction of which is constituted by a recess face such that the pad clip 14c is stabilized in the radial direction and the rotational direction in a state of being brought into contact with an inner half side in the radial direction of the middle coupling pin 20. Further, the center engaging portion 21 is proximate to inner wall portions 23, 23 of the two body portions 3a, 4a in the axial direction of the rotor 2 to achieve to position the pad clip 14c in the axial direction.
In contrast thereto, respective front half portions of the respective press arm portions 22, 22 are folded back to inner sides as shown by FIG. 13 to constitute elastic engaging portions 17, 17 and the respective elastic engaging portions 17, 17 are brought into contact with inner end edges proximate to the rotor 2 of outer peripheral edges in the radial direction of the pressure plates 13a, 13a. By the constitution, the two pressure plates 13a, 13a are exerted with the elastic force directed to an inner side in the radial direction and an elastic force in the direction of being separated from each other. Further, independent locking pins 36, 36 are provided for the two respective body portions 3a, 4a at portions proximate to inner sides in the radial direction of the outer body portion 3a and the inner body portion 4a. Further, portions of outer peripheral faces of the respective locking pins 36, 36 are brought into contact with inner end edges in the radial direction of either pressure plate 13a of the pressure plates 13a, 13a of the two pads 10a, 11a based on the elastic force of the pad clip 14c. 
In the case of a structure described in JP-A-2005-121174 mentioned above, by pertinently arranging the respective outer side, middle coupling pins 19, 20, the pad clip 14c, the respective locking pins 36, 36, the attitudes of the two pads 10a, 11a can be stabilized regardless of non braking time, braking time. That is, in non braking time, the press arm portions 22, 22 of the pad clip 14c provided between the middle coupling pin 20 and the outer peripheral edges proximate to the both ends in the rotational direction of the pressure plates 13a, 13a constituting the two pads 10a, 11a presses the inner peripheral edges in the radial direction of the two pressure plates 13a, 13a to the respective locking pins 36, 36. Therefore, the two pads 10a, 11a are not rattled by vibration or the like in accordance with running. However, also in the case of the structure described in Patent Reference 2 mentioned above, similar to the structure shown in FIG. 10 (B), the pad clip 14c is formed by folding back the elastic engaging portions 17, 17, and therefore, a dimension of a material plate before being folded back is increased.
That is, the pad clip 14c includes the press arm portions 22, 22 on the both sides in the rotational direction of the center engaging portion 21, and the respective elastic engaging portions 17, 17 are projected from the end portions of the two press arm portions 22, 22 to the two pads 10a, 11a. Further, the respective elastic engaging portions 17, 17 are formed by being folded back, and therefore, amounts of projecting portions in correspondence with the respective elastic engaging portions 17, 17 from the two press arm portions 22, 22 in a state of a material plate before being folded back are increased. Therefore, in a state of the material plate of the pad clip 14c, by presence of the center engaging portion 21 and the two press arm portions 22, 22, a dimension in the rotational direction of the rotor 2 is increased, the amounts of projecting the portions in correspondence with the respective elastic engaging portions 17, 17 are increased, thereby, also a dimension in the axial direction of the rotor 2 is increased. Therefore, in punching a material plate from a metal plate constituting a material, it is unavoidable that the interval between contiguous material plates is increased, and the blanking performance (yield) is deteriorated.